In case of ZFS and bcachefs, you also have native encryption, making LUKS obsolete.
I don’t think that it makes LUKS obsolete. LUKS encrypts the entire partition, but ZFS (and BTRFS too as I know) only encrypt the data and some of the metadata, the rest is kept as it is.
Data that is not encrypted can be modified from the outside (the checksums have to be updated of course), which can mean from a virus on a dual booted OS to an intruder/thief/whatever.
If you have read recently about the logofail attack, the same could happen with modifying the technical data of a filesystem, but it may be bad enough if they just swap the names of 2 of your snapshots if they just want to cause trouble.